Evaporative condenser with micro water drolets forming ultra thin film

ABSTRACT

Water evaporation with accompanying large amount of heat absorption is used in an apparatus and methods in cooling hot refrigerant in a condenser as result of work by an air conditioning compressor. A centrifugal water droplet generator and projector are designed with air flow modification of droplet travel paths for maximum even coating of condenser surfaces with thin water film for maximum evaporation efficiency. Vacuum is also used in the system for lowering of water evaporation temperature and carrying away moisture saturated air to further increase efficiency of condenser cooling.

BACKGROUND OF INVENTION

While many prior arts (U.S. Pat. Nos. 4,434,112; 4,438,635; 4,626,383; 4,974,422; and 6,766,655) claim use water evaporation as means to cool a condenser, virtually in all their inventions, water evaporation consists of only a very small portion of cooling while major cooling is done by fan or heat absorption by water. Prior art U.S. Pat. No. 6,338,257 hoping to evaporate a large amount of water gave no information of nozzle description, performance, or specification of absorbing material supposed to hold water to be evaporated. Examples of prior arts are many, failing to understand conditions and requirements of manipulating water to absorb heat from a source and achieve evaporative process in high efficiency.

In this invention majority work of cooling condenser is achieved by changing of phase of water from liquid to gas phase to provide absorption of heat. It is well known that the process of evaporation of 1 gram, or 1 cc, of water absorbs 544 calories of heat while the same amount of water absorbs only 1 calorie to increase 1 degree Fahrenheit. A number of conditions must be met with associated designs that maximize water evaporation on a complex physical shape of a Tube-fins type condenser.

Absorption of heat from a source requires water to cover as much of the surface of heat source as possible. However, too much water leads to the absorption of heat by water which is rather inefficient, since 1 gram (or cc) of water absorbs only 1 calorie of heat. We want water evaporation because evaporation of water absorbs heat far more efficiently as mentioned above. A uniform thin water film covering the heat source on one side with the other side exposed to atmosphere is the preferred configuration for water evaporation, since heat absorbed by water film has very short distance to travel to be in contact with air for evaporation. High air contact across the exposed side of the water film also helps evaporating the water. Another option to achieve high water evaporation rate is by lowering pressure surrounding the condenser. It is known from experiments that reducing air pressure to 6 inches of mercury reduces water evaporation temperature to 4° C. The question is whether reduction of air pressure reduces heat absorption by what amount based on heat output from compression of gas phase refrigerant produces high enough temperature for vacuum (at what degree—mm mercury) providing maximum water evaporation?

To produce an even coating of a thin water film over the entire surface of a Tube-fins condenser requires the water to be converted to a large number of very small uniform-sized droplets (experimental results in other areas of study) in the 50 micron range (0.002 inch diameter) and sprayed on the condenser surface until sufficient water is deposited to form a thin film. Fog size droplets at 5 to 10 micron range work even better but require machinery of greater capacity. Prior arts have indicated use of spray or drip nozzles have failed to understand the mechanism in generating uniform-sized and small enough water droplets. Water under pressure exiting a nozzle produces droplet sizes from small to large in distribution conforming to a typical bell curve. Most fine droplet agricultural sprayers produce around the 450 micron range with 100 to 200 PSI pressure. To achieve much smaller droplets the pump has to produce a much higher pressure, so it is not practical.

Also documented is that uniform-sized droplets can only be generated by a centrifugal spinner. Size of droplets is determined by rim speed of the spinner in centrifugal droplet generation methods. Direction of droplet travel can be modified by air current exemplified by an earlier invention U.S. Pat. No. 6,152,382 for coverage of spray droplets on complex forms.

Uniform-sized small droplet spray is essential in coating the condenser with a thin water film. Since dimension of a typical Tube-fins condenser is usually wide and tall, a special sprayer is needed to accommodate condenser(s) in sections. Vacuum is also provided to reduce water evaporation temperature. Water, in such small amount for operation of a domestic air conditioner, collected by the vacuum can be also reclaimed for reuse.

An earlier patent application utilizing a large fan to produce a negative pressure surrounding the condenser has shown in experiments that the amount of time to achieve the same temperature as in a conventional method using air to cool the condenser is 30% less, signifying considerable energy savings.

SUMMARY

The present invention relates to a modular condenser in air conditioning applications that is primarily cooled by water evaporation (change from liquid phase to gaseous phase). This invention serves to significantly increase the efficiency of cooling compressed refrigerant by not using outdoor hot air that has been the traditional practice of air conditioners whether a central or split system. Water is converted into very small uniform-sized droplets on the order of 50 microns and projected onto the complex and multifaceted condenser surface with assistance of air flow initiated inside the centrifugal spray generator. Water spray is accompanied by air flow supplied in tandem with vacuum governed by timer, air and fluid valves. The object is to first spray water droplets onto the condenser surfaces to form a thin water film cover. After the film is formed, water and air flow are shut off and a valve is opened on a vacuum line. Vacuum lowers pressure in the housing containing the condenser, boils the water, and carries moist air away. Heat is absorbed from condenser surfaces in the process of water phase change. The purpose is to shorten time compressor uses electricity.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated and form a part of this specification, illustrate embodiments of the invention, and together with the descriptions, serve to explain the principles of the invention.

FIG. 1 a is a section view of a water droplet generator and projector. It is a rotating device with slots covered with plastic screen. Water is sprayed onto the inner surface of rotating spinner and breaks into droplets at a vertical strand of the screen material, projecting them tangentially from rotating spinner surface. Compressed air is supplied through small tube openings on four sides of the compressed air column in center moving water droplets in multiple angles toward condensers.

FIG. 1 is a sectional drawing of a modified small rotating spinner to accommodate height of condensers.

FIG. 1 a is sectional drawing of a rotating spray generator with air modification of direction of travel of spray to reach the surface areas of the condenser.

FIG. 2 is a cut away view of a sealed condenser housing with a rotating sprayer being installed showing spatial relationship.

FIG. 3 is a cut away top view showing movement of water droplet spray and air flow.

FIG. 4 is a drawing showing the connection to a vacuum for facilitating evaporation of water sprayed on the condensers and carrying water vapor away.

FIG. 5 is a cut away sectional view of an evaporative condenser using a large suction fan to produce a negative pressure to lower water evaporation temperature facilitating conversion to vapor phase for rapid heat absorption

REFERENCE NUMERALS IN DRAWINGS

-   -   1. Droplet generator collar for attachment to motor     -   1 a. Droplet generator with slots for air and droplet flow     -   2. Motor shaft     -   3. Centrifugal droplet generator     -   4. Screen in droplet generator slot     -   5. Plastic rod with small channels for release of air pressure     -   6. Air channel     -   7. Airtight enclosure housing evaporators     -   8. Evaporator     -   9. Tube connected to vacuum     -   10. Rotation of centrifugal droplet generator     -   11. Direction of air and droplet flow     -   12. Plastic rod with channels for air flow     -   13. Tube with hole to dispense water     -   14. Bottom of enclosure     -   15. Motor     -   16. Large suction fan

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the preferred embodiments, it will be understood that they are not intended to limit the invention to those embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims.

As described above, the present invention provides an apparatus and methods employing water phase change as primary source of heat absorbance to cool hot refrigerant in a Tube-fins condenser of an air conditioner. More particularly, this apparatus pursues maximum efficiency in refrigerant heat transfer to a thin water film covering condenser surfaces; water is rapidly evaporated due to the short distance heat has to travel and the large surface area for water to evaporate. Water evaporation temperature is greatly lowered due to presence of vacuum or lower air pressure surrounding the condenser, increasing efficiency of evaporation with provision of removing water vapor.

It is essential the condenser(s) be housed in an air tight chamber FIGS. 2, 3; 7. A motorized centrifugal droplet generator FIGS. 1 a, 1, 2, and 3; 1 a either directly or magnetically coupled to the motor is capable of generating uniform-sized fog size (5 to 10 microns in diameter) or larger with electronic control with provision for air to exit the droplet generator and modify traveling directions of the airborne droplets. Small uniform-sized water droplets are essential in providing a thin water film covering the entire condenser surface area assisted by airflow. Formation of the droplets and provision for air flow is accomplished by screened slots FIGS. 1 and 1 a; 4. Droplet formation is provided by a perforated tube mounted inside the rotating droplet generator to the bottom of the housing and is controlled by a solenoid valve FIG. 1 a and 1; 13. Water droplets are generated when water reaches the vertical threads of the screen while generator is spinning. Motor speed and diameter of droplet generator determine droplet diameter of resulting droplet spray. Air inlet and outlet channels are also placed inside rotating droplet generator and anchored to bottom of housing FIG. 1 a and 1; 6 and 12. To completely cover all surfaces of a Tube-fins condenser arranged in the air-tight housing, direction of the uniform-sized droplets with accompanying air flow is important as illustrated in FIGS. 2 and 3; 11 in relationship with droplet generator FIGS. 2 and 3; 1 a. Vacuum connection as well as removal path of moisture content from water evaporation are shown in FIGS. 2; 9.

One evaporative condenser version as in FIG. 4 is using vacuum alone to lower water evaporation temperature as well as carrying away the water vapor. Another possible version as in FIG. 5 is to use a large suction fan to produce a pressure differential between input air and outlet air to produce lower pressure surrounding the condensers to lower water evaporation temperature. Air movements provided by the suction fan also help to evaporate water from the thin water film covering Tube-fins surfaces of the condensers and carry the water vapor away. 

1. An apparatus for cooling a refrigerant in a condenser for an air conditioner or refrigeration device comprising: Means for generating controlled uniform-sized water droplets with a rotating centrifugal droplet generator and projecting droplets to cover all surface areas of condenser(s) located on 4 sides of a sealed chamber surrounding the droplet generator, and means to alter traveling paths of droplets with air to deposit a thin water film on condenser surfaces, plus means to provide a vacuum to lower air pressure surrounding condenser to lower water evaporation temperature to increase water evaporation rate and absorption of heat from condenser surfaces while removing moisture in chamber during process of water evaporation; A large suction fan means to hasten water evaporation by air blowing on the water film On the condenser surface. a motorized rotating centrifugal droplet generator with open slots covered with a chemically inert screen means to generate small uniform-sized droplets and permit air flow to exit droplet generator altering travel directions of sprayed droplets covering virtually all surface areas of condenser, a perforated tube means to deliver water to inner surface of rotating droplet generator for atomization anchored to bottom of air tight chamber, a plastic air router means for delivery of air flow with multi-channels branching from a central tube and anchored to the chamber bottom, a vacuum inlet tube means for delivering of vacuum and removal of moist air.
 2. The apparatus as in claim 1, wherein said water droplet generator, sprayer, and air flow pattern modifier produce a uniform thin water film covering surfaces of condenser.
 3. The apparatus as in claim 2 wherein said thin water film provides a short path for heat from condenser to travel to the thin water film surface to be evaporated aiding efficiency of evaporation.
 4. The apparatus as in claims 1, 2, and 3 wherein said vacuum is provided for lowering of water evaporation temperature to increase rate of water evaporation leading to shortened time required for compressor operation than traditional air cooled method with hot outdoor air. 